On the List: What it Means to be an Endangered Species

The Endangered Species Act (ESA) was established in 1973 in response to a growing movement of citizens calling for the extinction of…well…extinction. The purpose of the ESA, as described by the US Supreme Court, is to “reverse and halt the trend toward species extinction, whatever the cost.” This noble and lofty goal is upheld primarily by the National Oceanic and Atmospheric Administration (NOAA) and the US Fish and Wildlife Service (FWS). The ESA requires that any action that is permitted, funded, or carried out by the federal government does not endanger the existence of any listed species, either directly or through the destruction of their critical habitat. The law also prohibits “taking” a listed species, or participating in commerce for a listed species. Before we go any deeper, here are some definitions you might need to know.

Take – taking a listed species doesn’t mean grabbing it and running away. The official definition is “to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect or attempt to engage in any such conduct.” This includes damaging the habitat of an animal in a way that causes harm or death by altering behavior or access to necessary resources.

Species – the definition for species includes subspecies, varieties, and distinct population segments (or DPS, which you can read more about here)

Listed – a species that has been designated as either Endangered or Threatened under the ESA

Critical Habitat – specific areas within or outside of a species range that contain physical or biological features necessary for recovery (more here)

Extinction – the termination of a species, after the death of the last individual

Extirpation – the termination of a species in one section of its range, though it still exists in other places

Gray wolves (Canis lupus) were extirpated from the western lower 48 by bounty hunting and prey decline, but began recolonizing the Rocky Mountains in the 1980’s. In 2006, the Rocky Mountain DPS was delisted! Photo from animalsake.com

The first law governing commerce in animals was enacted in 1900, but it wasn’t until the ESA that comprehensive protections for species in danger of extinction were made possible. In order to be protected under the ESA, a species must first be listed. Members of the public can submit a petition to consider a species, or the agencies can initiate the process all on their own. In order to be considered for listing, the species must meet one of the five criteria under section 4(a)(1). These criteria are:

  1. Its habitat or range are being or will be destroyed or changed
  2. It has been harvested too heavily, for any purpose
  3. It is declining due to disease or predation
  4. The existing regulations are not strong enough
  5. There are other factors affecting its continued existence

If the proposed species meets one of these criteria, a 90-day screening period begins. While candidate species are being considered for listing, economic factors are not allowed to be considered, and decisions must be “based solely on the best scientific and commercial data available”. This means that species should be listed based on the severity of their situation, not how many challenges to protection they face, how expensive it will be, or how many people may disagree. At the end of this screening period, the species is given one of three designations; “not warranted”, which means it does not qualify for listing, “warranted”, which means it continues on immediately, or “warranted but precluded”, which means it qualifies, but is of low priority so it will be tabled until action becomes necessary.

Bald eagles (Haliaeetus leucocephalus) were listed in 1963 with only 416 breeding pairs after suffering huge declines due to rampant use of DDT. The ESA served as an important tool to force the ban on DDT, and by 2006, there were 9,789 breeding pairs. Photo by Andy Morffew.

Species that are designated as warranted will move on to the next stage, where the agency may consider public comment and will designate critical habitat. If a species is eventually listed, after a whole lot more paperwork, time, and consideration, it will be designated as either Endangered or Threatened. Endangered species are in danger of becoming extinct, while Threatened species are in danger of becoming endangered. For listed species, a Recovery Plan is developed to lay out the exact steps the agency will take to ensure that the species returns to healthy population levels.

While this process seems like it is full of political mumbo-jumbo and legalese, it actually requires a lot of science to get it right. For instance, in order to develop a recovery plan, the agencies have to understand what the main causes of decline are, how the population is structured, the reproductive biology of the species, and what a healthy population actually looks like. Without answers to these questions, the recovery plan would be a map without roads, labels, a compass rose or even basic topography. To answer these questions, agencies employ an army of scientists and fund projects that are carried out by other institutions, non-profits, and universities. These scientists also track the progress of a species toward recovery to make sure that the ESA is accomplishing its stated goals.

Whooping cranes (Grus Americana) were listed in 1967 when there were only 43 birds left in the wild. In 2014, there were 440 wild birds, a 923% increase! Photo from audubon.org

So what does success look like? Delisting! Once a species has recovered, it is removed from the list. Species that were designated as Endangered will often be “downlisted” to Threatened on their path to recovery. The factors that an agency considers for delisting include whether the threat has been controlled, the growth of the population, and the stability of its habitat.

Over the life of the ESA, 28 species have been delisted due to successful recovery. While many species still struggle with barriers to recovery, including human activity, ecosystem changes, and climate change, the ESA is a good example of how important it is to have protections in place for at-risk species.



Liz Allyn

Conservation Made Simple










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